The singularity theorems in general relativity, via incompleteness of geodesics in all reasonable spacetimes, show that our universe must have singularities, where laws of physics break down, at its beginning, end or in between. Replacing classical geodesics with quantal (or Bohmian) trajectories, we show that the quantum potential they produce prevent such singularities from forming. Further we show that this potential for a condensate of gravitons gives rise to a cosmological constant with its correct observed value, and provides a viable explanation for dark energy and the late time accelerated expansion of the universe. In this picture, we also speculate on the evolution and ultimate fate of our universe.